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Draft North & East Metro Groundwater Management Area Plan 3-4 Ecosystems and Surface Waters The second part of Objective I deals with harm to ecosystems and negative impacts to surface Waters when groundwater is overused.The groundwater system is part of the water cycle, eventually destined to discharge to surface waters such as rivers, lakes, wetlands, or springs. Taking groundwater from water table and most artesian aquifers diverts water from surface waters or wetlands.Overuse of groundwater can significantly alter surface water features and the biological communities, recreation, and other uses that those waters supports. Surface water appropriations are governed by Minn. Stat., sec. 103G.285. Groundwater appropriations are governed by Minn. Stat., sec. 103G.287. Groundwater appropriations may also be subject to additional limits based on their surface water impacts as follows (Minn. Stat, sec. 103G.297, subd. 2): Groundwater appropriations that will have negative impacts to surface waters are subject to applicable provisions in section 103G.285. The DNR will use the surface water protections described in Minn. Stat., sec. 103G.285 as the minimum threshold for negative impacts when evaluating groundwater appropriations. However, surface-water pumping(appropriation) has a direct and immediate effect on flow or water level in the surface water features from which the water is withdrawn. When a surface appropriation is suspended there is an immediate effect on the water levels. The same is not true for groundwater appropriations. Determining whether groundwater appropriations have negative impacts to surface waters is complex. Generally, the effect on connected surface water features is both delayed and spread out or'flattened' in time and is typically distributed among multiple water features. Several thresholds that exist in law are helpful in determining if negative impacts are occurring in surface waters: 1. Appropriations from lakes listed in Bulletin 256 are limited to a total annual volume of water amounting to 1/2 acre-foot per acre of water basin (6 inches over the surface area of the water body) (Minn. Stat., sec. 103G.285, subd. 3).Also, appropriations from lakes less than 500 acres must be discouraged (Minn. Stat., sec. 103G.261, item d). 2. Appropriations taken directly from surface water bodies are limited according to the requirements establishing and enforcing protected flows for streams and rivers or protective elevations for lakes and wetlands (Minn.Stat.,sec. 103G.285).These are intended to accommodate the range of needs and uses of water bodies. For surface-water appropriations, consumptive appropriations may not be made from watercourses during periods of specified low flows (i.e. protected flows)or from lakes and wetlands when water levels are below the protective elevation (Minn.Stat., sec. 103G.285, subd. 2 and 3). 6 DNR Staff, 1968.An Inventory of Minnesota Lakes. Division of Water,Soils and Minerals, Minnesota Conservation Department P53